MEP-006A output voltage low

[Sparkyz911]

I'm on a rescue squad and we have this as our building backup generator...
NSN 6115-00-118-1243
MEP_006A Model 70-1900 Generator Alternating current. Synchronous brushless
V:120/208 - 240/416
A: 208-104
KW: 50/60
KVA: 62.5/75
Hz:50/60

The motor runs great and is in great shape. The genset is giving us fits. Regardless of the leg(s) you try to run on the output voltage is low. 120v running at 90v, 208v running about 180v. It holds 60 cycles just fine. Any idea what would cause the voltage to be about 30 low?? Bad regulator?? Bad armature?? Any help is greatly appreciated.

 

[Zed254]

If you don't have the TM check this out.....

manuals.chudov.com/Military-Generators/MEP-006A/TM-5-6115-545-12_Operator_Maintenance.pdf . Page 157/325 shows troubleshooting tips regarding voltage.


Parts here: igor.chudov.com/manuals/Military-Generators/MEP-006A/TM-9-6115-545-24_Parts.pdf

 

[Suprman]

Could be the regulator. The regulator/exciter box is not really sealed. Over years bugs, dust and gunk get in there. Does the voltage adjustment knob on the panel do anything? Have you verified the output with a meter? You can’t always trust the panel meter. When you close the contactor do you get a low voltage fault?

 

[Guyfang]

First off, all the TM's needed to repair the set are here in the TM forum. No need to go anyplace else.

When you you mesure at the load terminals, are all three phases low? Or just the two you need. Has this set ever worked right before? Or is the voltage problem just started to happen? Is TB1 set in the proper position? Has anyone put a different static Excitor in of late? If so, is it the right one. Need a little background info here.